I'm personally having trouble having vivid journeys. I see a few things -- a wolf, a moon, a tree -- but there isn't much of a story. I also can't seem to really make my way through a tunnel, I usually just see a door but lose focus or the vision goes away.

I drum at 180 bpm, focus my intention and repeat it as a mantra, then when I feel a shift in consciousness I do a heartbeat drum at 180 bpm, visualize an entryway, greet and state my intention to my guide, and try to go through a tunnel. Then I usually got distracted or nothing happens.

Does anyone have any tips on successful journeys? Any good online resources?

Am I simply struggling due to a lack of experience?

You may want to change your beat. Move the beat up in bpm until you find your "sweet spot". You may need to use a CD or other beat generator to first find the bpm, then you can replicate with your own drumming.
Shine!
Mark